1. Field of the Invention
The invention relates to a gas turbine arrangement having a rotor and at least two rows of turbine blades or vanes, a method for operating the gas turbine arrangement, and a turbine blade or vane for use in the gas turbine arrangement.
2. Brief Description of the Related Art
On account of the temperatures of the hot gases which surround them, turbine blades and vanes of gas turbines have to be cooled. Coolable blades or vanes for gas turbines with an internal cooling system have been disclosed, for example, by laid-open specification DE-A1 198 60 788, by EP-A1 0 534 586 or by EP-A1 1 094 200. Cooling air is guided out of a cooling passage located in the rotor into the internal cooling system and is then passed through discharge openings into the flow passage of the respective gas turbine.
One major problem with cooling systems of this type is a leakage stream of cooling air which escapes between turbine blades or vanes and/or rotating and static parts of the gas turbine. Sealing devices which are supposed to minimize the cooling air leakage stream at this location are known from EP-A1 1 094 200, U.S. Pat. No. 6,152,690, U.S. Pat. No. 6,086,329, U.S. Pat. No. 4,820,116, U.S. Pat. No. 4,626,169, U.S. Pat. No. 4,505,640, U.S. Pat. No. 4,439,107, U.S. Pat. No. 4,265,590 and DE-A 1 942 346.
Other documents disclose devices which serve the purpose of minimizing the leakage stream of cooling air and of introducing the remaining stream into the hot gases of the gas turbine with the minimum possible losses and turbulence or utilizing it in some other way. In this context, mention may be made, for example, of U.S. Pat. No. 5,211,533.
Furthermore, U.S. Pat. No. 5,800,124 discloses a seal in which the leakage stream is diverted onto the trailing edge of the turbine blade or vane in order for the platform to be cooled there by impingement cooling.
U.S. Pat. No. 6,077,035 has disclosed a metal diverter sheet which prevents the leakage stream between the rotor blades and introduces the cooling air between the guide vanes and rotor blades with low losses. U.S. Pat. No. 4,348,157 has disclosed a similar device.